Local Kubernetes Cluster on KVM

Introduction

I wanted to explore kubernetes even more for myself and for this blog. I've worked on pieces of this at work but not the totality of the work which I would like to understand for myself. I wanted, also to explore new tools and ways to leverage the power of kubernetes.

So far, I have been using minikube to do the deployments but there is an inherit restriction that comes with using a single bundled node. Sure, it is easy to get it up and running but at some point I had to use nodePort to go around the IP restriction. This is a restriction that you will have in an actual kubernetes cluster but I will show you later how to go around it. For now, let's just get a local cluster up and running.

Objective

I needed a local kubernetes cluster using all open source tools and easy to deploy. So I went with using KVM as the hypervisor layer and installed virt-manager for shallow management. As an OS, I wanted something light and made for kubernetes. As I already know of Rancher (being an easy way to deploy kubernetes and they have done a great job so far since the launch of their Rancer 2.0) I decided to try RancherOS. So let's see how all that works together.

Requirements

Let's start by thinking about what we actually need. Rancher, the dashboard they offer is going to need a VM by itself and they recommend 4GB of RAM. I only have 16GB of RAM on my machine so I'll have to do the math to see how much I can afford to give this dashboard and manager. By looking at the RancherOS hardware requirements, I can tell that by giving a each node 2GB of RAM I should be able to host a 3 node cluster and with 2 more for the dashboard that puts me right on 8GB of RAM. So we need to create 4 VMs with 2GB of RAM each.

Installing RancherOS

Once all 4 nodes have been created, when you boot into the RancherOS ISO do the following.

INFO

Because I was using libvirt, I was able to do virsh console <vm> and run these commands.

Virsh Console

If you are running these VMs on libvirt, then you can console into the box and run vi.

Give it a few minutes for the container to come up and the application as well. Meanwhile configure your /etc/hosts file on your machine.

192.168.122.5 rancher.kube.loco

Now that all that is out of the way, you can login to https://rancher.kube.loco and set your admin password and the url for Rancher.

Deploying Kubernetes

Now that everything is ready, let's deploy kubernetes the easy way.

At this point you should be greeted with a page that looks like the following.

Click on the Add Cluser

Make sure you choose Custom as a provider. Then fill in the Cluser Name in our case we'll call it kube.

Optionally, you can choose your Network Providor, in my case I chose Calico. Then I clicked on show advanced at the bottom right corner then expanded the newly shown tabAdvanced Cluster Options.

We will disable the Nginx Ingress and the Pod Security Policy Support for the time being. This will become more apparent why in the future, hopefully. Then hit Next.

Make sure that you select all 3 Node Roles. Set the Public Address and the Node Name to the first node and then copy the command and paste it on the first node.

Do the same for all the rest. Once the first docker image gets downloaded and ran you should see a message pop at the bottom.

Warning

Do NOT click done until you see all 3 nodes registered.

Finalizing

Now that you have 3 registered nodes, click Done and go grab yourself a cup of coffee. Maybe take a long walk, this will take time. Or if you are curious like me, you'd be looking at the logs, checking the containers in a quad pane tmux session.

After a long time has passed, our story ends with a refresh and a welcome with this page.

Welcome to your Kubernetes Cluster.

Conclusion

At this point, you can check that all the nodes are healthy and you got yourself a kubernetes cluster. In future blog posts we will explore an avenue to deploy multiple ingress controllers on the same cluster on the same port: 80 by giving them each an IP external to the cluster.

But for now, you got yourself a kubernetes cluster to play with. Enjoy.

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25 May 2019

Introduction

In the previous post in the kubernetes series, we deployed a small kubernetes cluster locally on KVM. In future posts we will be deploying more things into the cluster. This will enable us to test different projects, ingresses, service meshes, and more from the open source community, build specifically for kubernetes. To help with this future quest, we will be leveraging a kubernetes package

Introduction

I wanted to explore kubernetes even more for myself and for this blog. I've worked on pieces of this at work but not the totality of the work which I would like to understand for myself. I wanted, also to explore new tools and ways to leverage the power of kubernetes.

If you have ever worked with kubernetes, you'd know that minikube out of the box does not give you what you need for a quick setup. I'm sure you can go minikube start, everything's up... Great...kubectl get pods -n kube-system. It works, let's move on...

But what if it's not let's move on to something else. We need to look at this as a local test environment in capabilities.

When I first started using ansible, I did not know about molecule. It was a bit daunting to start a role from scratch and trying to develop it without having the ability to test. Then a co-worker of mine told me about molecule and everything changed.